The Tor Browser: ipc/chromium/src/base/task.h@6474c204b198 (annotated)

ipc/chromium/src/base/task.h@6474c204b198 (annotated)

ipc/chromium/src/base/task.h

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 #ifndef BASE_TASK_H_
 #define BASE_TASK_H_
 #include "base/non_thread_safe.h"
 #include "base/revocable_store.h"
 #include "base/tracked.h"
 #include "base/tuple.h"
 // Task ------------------------------------------------------------------------
 //
 // A task is a generic runnable thingy, usually used for running code on a
 // different thread or for scheduling future tasks off of the message loop.
 class Task : public tracked_objects::Tracked {
  public:
   Task() {}
   virtual ~Task() {}
   // Tasks are automatically deleted after Run is called.
   virtual void Run() = 0;
 };
 class CancelableTask : public Task {
  public:
   // Not all tasks support cancellation.
   virtual void Cancel() = 0;
 };
 // Scoped Factories ------------------------------------------------------------
 //
 // These scoped factory objects can be used by non-refcounted objects to safely
 // place tasks in a message loop.  Each factory guarantees that the tasks it
 // produces will not run after the factory is destroyed.  Commonly, factories
 // are declared as class members, so the class' tasks will automatically cancel
 // when the class instance is destroyed.
 //
 // Exampe Usage:
 //
 // class MyClass {
 //  private:
 //   // This factory will be used to schedule invocations of SomeMethod.
 //   ScopedRunnableMethodFactory<MyClass> some_method_factory_;
 //
 //  public:
 //   // It is safe to suppress warning 4355 here.
 //   MyClass() : some_method_factory_(this) { }
 //
 //   void SomeMethod() {
 //     // If this function might be called directly, you might want to revoke
 //     // any outstanding runnable methods scheduled to call it.  If it's not
 //     // referenced other than by the factory, this is unnecessary.
 //     some_method_factory_.RevokeAll();
 //     ...
 //   }
 //
 //   void ScheduleSomeMethod() {
 //     // If you'd like to only only have one pending task at a time, test for
 //     // |empty| before manufacturing another task.
 //     if (!some_method_factory_.empty())
 //       return;
 //
 //     // The factories are not thread safe, so always invoke on
 //     // |MessageLoop::current()|.
 //     MessageLoop::current()->PostDelayedTask(FROM_HERE,
 //         some_method_factory_.NewRunnableMethod(&MyClass::SomeMethod),
 //         kSomeMethodDelayMS);
 //   }
 // };
 // A ScopedTaskFactory produces tasks of type |TaskType| and prevents them from
 // running after it is destroyed.
 template<class TaskType>
 class ScopedTaskFactory : public RevocableStore {
  public:
   ScopedTaskFactory() { }
   // Create a new task.
   inline TaskType* NewTask() {
     return new TaskWrapper(this);
   }
   class TaskWrapper : public TaskType, public NonThreadSafe {
    public:
     explicit TaskWrapper(RevocableStore* store) : revocable_(store) { }
     virtual void Run() {
       if (!revocable_.revoked())
         TaskType::Run();
     }
    private:
     Revocable revocable_;
     DISALLOW_EVIL_CONSTRUCTORS(TaskWrapper);
   };
  private:
   DISALLOW_EVIL_CONSTRUCTORS(ScopedTaskFactory);
 };
 // A ScopedRunnableMethodFactory creates runnable methods for a specified
 // object.  This is particularly useful for generating callbacks for
 // non-reference counted objects when the factory is a member of the object.
 template<class T>
 class ScopedRunnableMethodFactory : public RevocableStore {
  public:
   explicit ScopedRunnableMethodFactory(T* object) : object_(object) { }
   template <class Method>
   inline Task* NewRunnableMethod(Method method) {
     typedef typename ScopedTaskFactory<RunnableMethod<
         Method, Tuple0> >::TaskWrapper TaskWrapper;
     TaskWrapper* task = new TaskWrapper(this);
     task->Init(object_, method, MakeTuple());
     return task;
   }
   template <class Method, class A>
   inline Task* NewRunnableMethod(Method method, const A& a) {
     typedef typename ScopedTaskFactory<RunnableMethod<
         Method, Tuple1<A> > >::TaskWrapper TaskWrapper;
     TaskWrapper* task = new TaskWrapper(this);
     task->Init(object_, method, MakeTuple(a));
     return task;
   }
   template <class Method, class A, class B>
   inline Task* NewRunnableMethod(Method method, const A& a, const B& b) {
     typedef typename ScopedTaskFactory<RunnableMethod<
         Method, Tuple2<A, B> > >::TaskWrapper TaskWrapper;
     TaskWrapper* task = new TaskWrapper(this);
     task->Init(object_, method, MakeTuple(a, b));
     return task;
   }
   template <class Method, class A, class B, class C>
   inline Task* NewRunnableMethod(Method method,
                                  const A& a,
                                  const B& b,
                                  const C& c) {
     typedef typename ScopedTaskFactory<RunnableMethod<
         Method, Tuple3<A, B, C> > >::TaskWrapper TaskWrapper;
     TaskWrapper* task = new TaskWrapper(this);
     task->Init(object_, method, MakeTuple(a, b, c));
     return task;
   }
   template <class Method, class A, class B, class C, class D>
   inline Task* NewRunnableMethod(Method method,
                                  const A& a,
                                  const B& b,
                                  const C& c,
                                  const D& d) {
     typedef typename ScopedTaskFactory<RunnableMethod<
         Method, Tuple4<A, B, C, D> > >::TaskWrapper TaskWrapper;
     TaskWrapper* task = new TaskWrapper(this);
     task->Init(object_, method, MakeTuple(a, b, c, d));
     return task;
   }
   template <class Method, class A, class B, class C, class D, class E>
   inline Task* NewRunnableMethod(Method method,
                                  const A& a,
                                  const B& b,
                                  const C& c,
                                  const D& d,
                                  const E& e) {
     typedef typename ScopedTaskFactory<RunnableMethod<
         Method, Tuple5<A, B, C, D, E> > >::TaskWrapper TaskWrapper;
     TaskWrapper* task = new TaskWrapper(this);
     task->Init(object_, method, MakeTuple(a, b, c, d, e));
     return task;
   }
  protected:
   template <class Method, class Params>
   class RunnableMethod : public Task {
    public:
     RunnableMethod() { }
     void Init(T* obj, Method meth, const Params& params) {
       obj_ = obj;
       meth_ = meth;
       params_ = params;
     }
     virtual void Run() { DispatchToMethod(obj_, meth_, params_); }
    private:
     T* obj_;
     Method meth_;
     Params params_;
     DISALLOW_EVIL_CONSTRUCTORS(RunnableMethod);
   };
  private:
   T* object_;
   DISALLOW_EVIL_CONSTRUCTORS(ScopedRunnableMethodFactory);
 };
 // General task implementations ------------------------------------------------
 // Task to delete an object
 template<class T>
 class DeleteTask : public CancelableTask {
  public:
   explicit DeleteTask(T* obj) : obj_(obj) {
   }
   virtual void Run() {
     delete obj_;
   }
   virtual void Cancel() {
     obj_ = NULL;
   }
  private:
   T* obj_;
 };
 // Task to Release() an object
 template<class T>
 class ReleaseTask : public CancelableTask {
  public:
   explicit ReleaseTask(T* obj) : obj_(obj) {
   }
   virtual void Run() {
     if (obj_)
       obj_->Release();
   }
   virtual void Cancel() {
     obj_ = NULL;
   }
  private:
   T* obj_;
 };
 // RunnableMethodTraits --------------------------------------------------------
 //
 // This traits-class is used by RunnableMethod to manage the lifetime of the
 // callee object.  By default, it is assumed that the callee supports AddRef
 // and Release methods.  A particular class can specialize this template to
 // define other lifetime management.  For example, if the callee is known to
 // live longer than the RunnableMethod object, then a RunnableMethodTraits
 // struct could be defined with empty RetainCallee and ReleaseCallee methods.
 template <class T>
 struct RunnableMethodTraits {
   static void RetainCallee(T* obj) {
     obj->AddRef();
   }
   static void ReleaseCallee(T* obj) {
     obj->Release();
   }
 };
 // RunnableMethod and RunnableFunction -----------------------------------------
 //
 // Runnable methods are a type of task that call a function on an object when
 // they are run. We implement both an object and a set of NewRunnableMethod and
 // NewRunnableFunction functions for convenience. These functions are
 // overloaded and will infer the template types, simplifying calling code.
 //
 // The template definitions all use the following names:
 // T                - the class type of the object you're supplying
 //                    this is not needed for the Static version of the call
 // Method/Function  - the signature of a pointer to the method or function you
 //                    want to call
 // Param            - the parameter(s) to the method, possibly packed as a Tuple
 // A                - the first parameter (if any) to the method
 // B                - the second parameter (if any) to the mathod
 //
 // Put these all together and you get an object that can call a method whose
 // signature is:
 //   R T::MyFunction([A[, B]])
 //
 // Usage:
 // PostTask(FROM_HERE, NewRunnableMethod(object, &Object::method[, a[, b]])
 // PostTask(FROM_HERE, NewRunnableFunction(&function[, a[, b]])
 // RunnableMethod and NewRunnableMethod implementation -------------------------
 template <class T, class Method, class Params>
 class RunnableMethod : public CancelableTask,
                        public RunnableMethodTraits<T> {
  public:
   RunnableMethod(T* obj, Method meth, const Params& params)
       : obj_(obj), meth_(meth), params_(params) {
     this->RetainCallee(obj_);
   }
   ~RunnableMethod() {
     ReleaseCallee();
   }
   virtual void Run() {
     if (obj_)
       DispatchToMethod(obj_, meth_, params_);
   }
   virtual void Cancel() {
     ReleaseCallee();
   }
  private:
   void ReleaseCallee() {
     if (obj_) {
       RunnableMethodTraits<T>::ReleaseCallee(obj_);
       obj_ = NULL;
     }
   }
   T* obj_;
   Method meth_;
   Params params_;
 };
 template <class T, class Method>
 inline CancelableTask* NewRunnableMethod(T* object, Method method) {
   return new RunnableMethod<T, Method, Tuple0>(object, method, MakeTuple());
 }
 template <class T, class Method, class A>
 inline CancelableTask* NewRunnableMethod(T* object, Method method, const A& a) {
   return new RunnableMethod<T, Method, Tuple1<A> >(object,
                                                    method,
                                                    MakeTuple(a));
 }
 template <class T, class Method, class A, class B>
 inline CancelableTask* NewRunnableMethod(T* object, Method method,
 const A& a, const B& b) {
   return new RunnableMethod<T, Method, Tuple2<A, B> >(object, method,
                                                       MakeTuple(a, b));
 }
 template <class T, class Method, class A, class B, class C>
 inline CancelableTask* NewRunnableMethod(T* object, Method method,
                                           const A& a, const B& b, const C& c) {
   return new RunnableMethod<T, Method, Tuple3<A, B, C> >(object, method,
                                                          MakeTuple(a, b, c));
 }
 template <class T, class Method, class A, class B, class C, class D>
 inline CancelableTask* NewRunnableMethod(T* object, Method method,
                                           const A& a, const B& b,
                                           const C& c, const D& d) {
   return new RunnableMethod<T, Method, Tuple4<A, B, C, D> >(object, method,
                                                             MakeTuple(a, b,
                                                                       c, d));
 }
 template <class T, class Method, class A, class B, class C, class D, class E>
 inline CancelableTask* NewRunnableMethod(T* object, Method method,
                                           const A& a, const B& b,
                                           const C& c, const D& d, const E& e) {
   return new RunnableMethod<T,
                             Method,
                             Tuple5<A, B, C, D, E> >(object,
                                                     method,
                                                     MakeTuple(a, b, c, d, e));
 }
 template <class T, class Method, class A, class B, class C, class D, class E,
           class F>
 inline CancelableTask* NewRunnableMethod(T* object, Method method,
                                           const A& a, const B& b,
                                           const C& c, const D& d, const E& e,
                                           const F& f) {
   return new RunnableMethod<T,
                             Method,
                             Tuple6<A, B, C, D, E, F> >(object,
                                                        method,
                                                        MakeTuple(a, b, c, d, e,
                                                                  f));
 }
 template <class T, class Method, class A, class B, class C, class D, class E,
           class F, class G>
 inline CancelableTask* NewRunnableMethod(T* object, Method method,
                                          const A& a, const B& b,
                                          const C& c, const D& d, const E& e,
                                          const F& f, const G& g) {
   return new RunnableMethod<T,
                             Method,
                             Tuple7<A, B, C, D, E, F, G> >(object,
                                                           method,
                                                           MakeTuple(a, b, c, d,
                                                                     e, f, g));
 }
 // RunnableFunction and NewRunnableFunction implementation ---------------------
 template <class Function, class Params>
 class RunnableFunction : public CancelableTask {
  public:
   RunnableFunction(Function function, const Params& params)
       : function_(function), params_(params) {
   }
   ~RunnableFunction() {
   }
   virtual void Run() {
     if (function_)
       DispatchToFunction(function_, params_);
   }
   virtual void Cancel() {
     function_ = NULL;
   }
  private:
   Function function_;
   Params params_;
 };
 template <class Function>
 inline CancelableTask* NewRunnableFunction(Function function) {
   return new RunnableFunction<Function, Tuple0>(function, MakeTuple());
 }
 template <class Function, class A>
 inline CancelableTask* NewRunnableFunction(Function function, const A& a) {
   return new RunnableFunction<Function, Tuple1<A> >(function, MakeTuple(a));
 }
 template <class Function, class A, class B>
 inline CancelableTask* NewRunnableFunction(Function function,
                                            const A& a, const B& b) {
   return new RunnableFunction<Function, Tuple2<A, B> >(function,
                                                        MakeTuple(a, b));
 }
 template <class Function, class A, class B, class C>
 inline CancelableTask* NewRunnableFunction(Function function,
                                            const A& a, const B& b,
                                            const C& c) {
   return new RunnableFunction<Function, Tuple3<A, B, C> >(function,
                                                           MakeTuple(a, b, c));
 }
 template <class Function, class A, class B, class C, class D>
 inline CancelableTask* NewRunnableFunction(Function function,
                                            const A& a, const B& b,
                                            const C& c, const D& d) {
   return new RunnableFunction<Function, Tuple4<A, B, C, D> >(function,
                                                              MakeTuple(a, b,
                                                                        c, d));
 }
 template <class Function, class A, class B, class C, class D, class E>
 inline CancelableTask* NewRunnableFunction(Function function,
                                            const A& a, const B& b,
                                            const C& c, const D& d,
                                            const E& e) {
   return new RunnableFunction<Function, Tuple5<A, B, C, D, E> >(function,
                                                                 MakeTuple(a, b,
                                                                           c, d,
                                                                           e));
 }
 // Callback --------------------------------------------------------------------
 //
 // A Callback is like a Task but with unbound parameters. It is basically an
 // object-oriented function pointer.
 //
 // Callbacks are designed to work with Tuples.  A set of helper functions and
 // classes is provided to hide the Tuple details from the consumer.  Client
 // code will generally work with the CallbackRunner base class, which merely
 // provides a Run method and is returned by the New* functions. This allows
 // users to not care which type of class implements the callback, only that it
 // has a certain number and type of arguments.
 //
 // The implementation of this is done by CallbackImpl, which inherits
 // CallbackStorage to store the data. This allows the storage of the data
 // (requiring the class type T) to be hidden from users, who will want to call
 // this regardless of the implementor's type T.
 //
 // Note that callbacks currently have no facility for cancelling or abandoning
 // them. We currently handle this at a higher level for cases where this is
 // necessary. The pointer in a callback must remain valid until the callback
 // is made.
 //
 // Like Task, the callback executor is responsible for deleting the callback
 // pointer once the callback has executed.
 //
 // Example client usage:
 //   void Object::DoStuff(int, string);
 //   Callback2<int, string>::Type* callback =
 //       NewCallback(obj, &Object::DoStuff);
 //   callback->Run(5, string("hello"));
 //   delete callback;
 // or, equivalently, using tuples directly:
 //   CallbackRunner<Tuple2<int, string> >* callback =
 //       NewCallback(obj, &Object::DoStuff);
 //   callback->RunWithParams(MakeTuple(5, string("hello")));
 // Base for all Callbacks that handles storage of the pointers.
 template <class T, typename Method>
 class CallbackStorage {
  public:
   CallbackStorage(T* obj, Method meth) : obj_(obj), meth_(meth) {
   }
  protected:
   T* obj_;
   Method meth_;
 };
 // Interface that is exposed to the consumer, that does the actual calling
 // of the method.
 template <typename Params>
 class CallbackRunner {
  public:
   typedef Params TupleType;
   virtual ~CallbackRunner() {}
   virtual void RunWithParams(const Params& params) = 0;
   // Convenience functions so callers don't have to deal with Tuples.
   inline void Run() {
     RunWithParams(Tuple0());
   }
   template <typename Arg1>
   inline void Run(const Arg1& a) {
     RunWithParams(Params(a));
   }
   template <typename Arg1, typename Arg2>
   inline void Run(const Arg1& a, const Arg2& b) {
     RunWithParams(Params(a, b));
   }
   template <typename Arg1, typename Arg2, typename Arg3>
   inline void Run(const Arg1& a, const Arg2& b, const Arg3& c) {
     RunWithParams(Params(a, b, c));
   }
   template <typename Arg1, typename Arg2, typename Arg3, typename Arg4>
   inline void Run(const Arg1& a, const Arg2& b, const Arg3& c, const Arg4& d) {
     RunWithParams(Params(a, b, c, d));
   }
   template <typename Arg1, typename Arg2, typename Arg3,
             typename Arg4, typename Arg5>
   inline void Run(const Arg1& a, const Arg2& b, const Arg3& c,
                   const Arg4& d, const Arg5& e) {
     RunWithParams(Params(a, b, c, d, e));
   }
 };
 template <class T, typename Method, typename Params>
 class CallbackImpl : public CallbackStorage<T, Method>,
                      public CallbackRunner<Params> {
  public:
   CallbackImpl(T* obj, Method meth) : CallbackStorage<T, Method>(obj, meth) {
   }
   virtual void RunWithParams(const Params& params) {
     // use "this->" to force C++ to look inside our templatized base class; see
     // Effective C++, 3rd Ed, item 43, p210 for details.
     DispatchToMethod(this->obj_, this->meth_, params);
   }
 };
 // 0-arg implementation
 struct Callback0 {
   typedef CallbackRunner<Tuple0> Type;
 };
 template <class T>
 typename Callback0::Type* NewCallback(T* object, void (T::*method)()) {
   return new CallbackImpl<T, void (T::*)(), Tuple0 >(object, method);
 }
 // 1-arg implementation
 template <typename Arg1>
 struct Callback1 {
   typedef CallbackRunner<Tuple1<Arg1> > Type;
 };
 template <class T, typename Arg1>
 typename Callback1<Arg1>::Type* NewCallback(T* object,
                                             void (T::*method)(Arg1)) {
   return new CallbackImpl<T, void (T::*)(Arg1), Tuple1<Arg1> >(object, method);
 }
 // 2-arg implementation
 template <typename Arg1, typename Arg2>
 struct Callback2 {
   typedef CallbackRunner<Tuple2<Arg1, Arg2> > Type;
 };
 template <class T, typename Arg1, typename Arg2>
 typename Callback2<Arg1, Arg2>::Type* NewCallback(
     T* object,
     void (T::*method)(Arg1, Arg2)) {
   return new CallbackImpl<T, void (T::*)(Arg1, Arg2),
       Tuple2<Arg1, Arg2> >(object, method);
 }
 // 3-arg implementation
 template <typename Arg1, typename Arg2, typename Arg3>
 struct Callback3 {
   typedef CallbackRunner<Tuple3<Arg1, Arg2, Arg3> > Type;
 };
 template <class T, typename Arg1, typename Arg2, typename Arg3>
 typename Callback3<Arg1, Arg2, Arg3>::Type* NewCallback(
     T* object,
     void (T::*method)(Arg1, Arg2, Arg3)) {
   return new CallbackImpl<T,  void (T::*)(Arg1, Arg2, Arg3),
       Tuple3<Arg1, Arg2, Arg3> >(object, method);
 }
 // 4-arg implementation
 template <typename Arg1, typename Arg2, typename Arg3, typename Arg4>
 struct Callback4 {
   typedef CallbackRunner<Tuple4<Arg1, Arg2, Arg3, Arg4> > Type;
 };
 template <class T, typename Arg1, typename Arg2, typename Arg3, typename Arg4>
 typename Callback4<Arg1, Arg2, Arg3, Arg4>::Type* NewCallback(
     T* object,
     void (T::*method)(Arg1, Arg2, Arg3, Arg4)) {
   return new CallbackImpl<T, void (T::*)(Arg1, Arg2, Arg3, Arg4),
       Tuple4<Arg1, Arg2, Arg3, Arg4> >(object, method);
 }
 // 5-arg implementation
 template <typename Arg1, typename Arg2, typename Arg3,
           typename Arg4, typename Arg5>
 struct Callback5 {
   typedef CallbackRunner<Tuple5<Arg1, Arg2, Arg3, Arg4, Arg5> > Type;
 };
 template <class T, typename Arg1, typename Arg2,
           typename Arg3, typename Arg4, typename Arg5>
 typename Callback5<Arg1, Arg2, Arg3, Arg4, Arg5>::Type* NewCallback(
     T* object,
     void (T::*method)(Arg1, Arg2, Arg3, Arg4, Arg5)) {
   return new CallbackImpl<T, void (T::*)(Arg1, Arg2, Arg3, Arg4, Arg5),
       Tuple5<Arg1, Arg2, Arg3, Arg4, Arg5> >(object, method);
 }
 // An UnboundMethod is a wrapper for a method where the actual object is
 // provided at Run dispatch time.
 template <class T, class Method, class Params>
 class UnboundMethod {
  public:
   UnboundMethod(Method m, Params p) : m_(m), p_(p) {}
   void Run(T* obj) const {
     DispatchToMethod(obj, m_, p_);
   }
  private:
   Method m_;
   Params p_;
 };
 #endif  // BASE_TASK_H_

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ipc/chromium/src/base/task.h@6474c204b198 (annotated)

ipc/chromium/src/base/task.h